PCI interrupt allocation question..
ticso at cicely12.cicely.de
Fri Jan 16 08:39:47 PST 2004
On Tue, Jan 13, 2004 at 04:14:10PM -0800, Julian Elischer wrote:
> On Wed, 14 Jan 2004, Stijn Hoop wrote:
> > On Tue, Jan 13, 2004 at 03:26:00PM -0800, Julian Elischer wrote:
> > > The kernel includes teh ichsmb driver to try access the SMBus
> > > for temperature reading reasons (yes I know I can do it other ways..)
> > >
> > > Any thoughts that move me towards getting th eichsmb driver working on
> > > this machine are welcome.
> > Make sure that the mainboard really does support SMBus -- it turns out that
> > this is optional. The ICH docs talk about a bit that should be enabled in the
> > PCI config when SMB is present. I ran into this once, it should be documented
> > in the archives (of -current off the top of my head). OTOH, I didn't even
> > succeed in getting an ichsmb device probed so this might be something totally
> > unrelated.
SMBus is absolutely not optional because it's required for SPD eeproms.
> > FWIW, I had to try other ways to get the temperature (xmbmon & related). I
> > don't have the box anymore or I'd show you the exact config...
> xmbmon uses the SMBus to read the temperatures but it does it from
> userland using direct read and write operations
> and when there are timing glitches caused by the process not getting
> scheduled quite quick enough you get garbage results..
> teh theory is that the kernel driver wouldn't be susceptible to this
> but it looks like unless I resort to polling I will not be able to use
> it because it relies on the interrupts and they are not being delivered.
ichsmb(4) does a different addressing on smbus as other smbus drivers.
I'm about to validate all SMBus drivers to harmonise this point.
Also software regulary forgets about different smb.h include path on 5.x
> ASUS motherboards actually turn off the SMBus. (why?)
A very good question - I'm in tight contact with Asus germany to get
that answered, but even they doesn't seem to get a satisfying answer
It seems that they don't want customers to tamper with SMBus :(
> So you need to turn it back on before you can read the temperatures..
Well - it's evil after all, because I sell add on products for SMBus
for which ACPI is not an option.
B.Walter BWCT http://www.bwct.de
ticso at bwct.de info at bwct.de
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